Testing a Hypothesis
by Loki Mischeif-Maker
Summary: Pushing Sirius into the family circle always seemed to end in disaster. Still, even after getting sent home early from Bellatrix's wedding reception, Regulus couldn't help but admit that life with his brother was always interesting.


**Disclaimer: **I do not own anything in the Potterverse; JK Rowling does. I only fangirl both Black brothers something terrible.

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You can always tell when it's the Black family that organized the wedding. There seems to be something programmed in our genes to find bats both festive and appropriate for every occasion. My aunt tried to talk Cygnus out of it, but then Sirius commented that the bats at least matched the bride's personality and, ignoring the implied insult to his eldest daughter, my uncle used it as another excuse— the first was tradition— to fill the reception hall with conjured bats.

Lately, there's also been another sign: twice now my cat's ended up in a drink.

It actually took me a minute to realize that Anna's frantic mewing was coming from _inside_ the wine barrel Sirius was standing beside the first time. I ran over to find her churning the wine as if swimming a marathon and yowling piteously. She scratched me by accident as I lifted her out.

"Sirius, _why_ are you trying to drown my cat?" I demanded.

Sirius looked over at me innocently, as if he hadn't heard her splashing and yowling beside him. "I gave you the cat, Reggie," he pointed out. "Why would I then try to drown her a year later?"

"If I knew, would I ask?" I said as my tabby snuggled against my chest in a most uncatlike way. It was obvious she'd been terrified. "But knowing _you_, it is far too much of a coincidence that you're standing right beside the wine barrel she was in."

"I did _not_ try to drown her," Sirius repeated indignantly. "She was merely standing on the top of the barrel when I tested a hypothesis."

Rabastan Lestrange, the little brother of the groom and probably my best friend, came over to join us. "This I have to hear. What hypothesis was your blood-traitor of a brother testing?"

"He is _not_ a blood-traitor," I muttered.

"Well, not yet," Sirius said fairly. "Not entirely, at least. Anyway, the hypothesis I was testing, Lestrange, is that cats are imperturbable. Clearly they aren't."

"How could you not know that?" I demanded. "If she were, she wouldn't have taken a bite out of James Potter on the Hogwarts Express on the way home from school!" I shook my head, realized that this conversation was going nowhere, and changed the subject. "And why can't you call him Rabastan? His brother _did_ just marry Bella."

"_Because_ his brother just married Bella," Sirius replied airily. He looked into the barrel. The wine hadn't settled from Anna's churning, and long grey and black cat hairs were bobbing in it. "I wonder if that's still drinkable. . . ."

"Probably, with some spells none of the three of us know," I told him, and began digging through my pockets for my wand. "Speaking of spells, if no one's looking I'm going to dry Anna and me off. Thanks to Sirius we're soaked."

Sirius pulled his own wand out of his robes. "Here— I know the spell. And anyway, it _was_ kinda my fault."

"_Kinda?_" Rabastan murmured. "Try completely."

"I'm not letting you wave that thing anywhere near me!" I exclaimed. "I saw what happened to Pettigrew last time you tried to help someone using a spell."

Sirius sighed theatrically. "That was a new spell and an accident," he explained for probably the fortieth time. "And anyway, I didn't hurt Peter that bad, I just overdid it a li—"

"I'll do it," Rabastan interrupted. "It beats getting caught in the crossfire from you two, at any rate."

"I've _got_ it," I growled, tipping my struggling cat into Sirius's arms and pulling out my own wand. "Now is or isn't anyone looking?"

"Er . . . is," Rabastan replied.

Before either Sirius or I could reply, our father did. "Dare I ask what the three of you have gotten into now?"

Anna, who never cared much for Sirius, leapt back into my arms as he turned around to look sheepishly at him. "Just drying spells, Dad, I promise." Under his breath, he added, "I'm not stupid enough to curse Lestrange to Timbuktu in the middle of a wedding reception."

Rabastan shot him a nasty look, but if Dad heard he pretended not to. I think he was still sort of in denial about Sirius the Gryffindor and preferred to think of my brother as a rebellious prankster who would eventually come to his senses— it was Mum who couldn't wait to wash her hands of him. "Let me rephrase, then," Dad said impatiently. "_Why_ do you need drying spells?"

"Because Sirius was trying to drown my cat," I told him.

Sirius let out another theatrical sigh. "For the second time, Reggie, I was _not_. I was just—"

"Trying to test a hypothesis," I finished for him. "I heard, and frankly I found it the stupidest excuse you've ever given me. Look, Sirius, I know you would've fished her out before she died, it was putting her in the barrel in the first place I don't like—"

"_Boys_," our father interrupted warningly. He glanced over at Rabastan. "And where do you come in?"

"I wanted to see what Sirius's latest excuse was," he answered with a shrug.

"Well . . . yes, he is quite inventive, isn't he?" Dad mumbled, looking back over at Sirius uncomfortably and beginning to toy with his glasses— a sure sign he wasn't quite sure what to think and a habit that I had unfortunately picked up from him. "Dare I ask what you were trying to drown your brother's cat _in_?" he asked finally.

Sirius gestured wordlessly towards the wine barrel.

Dad looked down at the cat hair still bobbing serenely in the blood-colored liquid. "Does that thing ever stop shedding? And can you ever behave?" he asked absently. He glanced around. "I know there's a house elf around here somewhere who can deal with these things," he muttered.

"So what's the boy into now, Orion?"

All four of us jumped, and Dad turned around to stare in surprise at Mum. "I told you I'd handle it, Walburga—" he started.

"Well?" Mum demanded. "How far have you gotten?"

"Sirius pushed Regulus's cat into a barrel of wine," Dad supplied. Sometimes I wondered if he wasn't afraid of Mum, and Merlin knows no one would've blamed him if he was. She can be quite scary sometimes, and one of those times was now.

Mum sighed dramatically, but unlike Sirius, she meant it. "Honestly, with as much trouble as he gets into when we're only on the other side of the room, it's a surprise we only get a few owls a year from the headmaster. I would think once a day would be more reflective—"

"_Mum_!" Sirius interrupted indignantly.

"Let's leave it at this, Sirius: I can hardly wait another four years when I will finally be able to wash my hands of you!"

"That makes two of us," Sirius snapped, and it was the beginning of another fight.

Dad and I exchanged exasperated glances. Dad rather agreed with Mum on most of the issues and I could almost understand why Sirius wanted to be grown up and out of her hair, but both of us would rather they not yell at each other in public. Or at home, really, but I'd settle for never hearing another hundred-decibel discussion of Sirius's faults in the middle of Diagon Alley.

Fortunately, Mrs. Lestrange came to rescue us. "What's the matter here?" she asked, wandering over.

Mum and Sirius shut up immediately, and both of them even had the grace to look embarrassed about it.

"Hi Mum," said Rabastan, perfectly cheerfully. "Sirius had a go at drowning Reg's cat in a barrel of wine. I think Reg took it better than Mrs. Black."

"I think _Anna_ took it better than Mum," I pointed out to him in an undertone.

"Well," Mrs. Lestrange observed, "it's getting a bit late and perhaps these three are a bit young to be here all night. . . ."

"What did _I_ do?" Rabastan demanded.

"We're both younger than Sirius and the most inconspicious excuse to send him home is that he's thirteen," I murmured.

Rabastan hardly looked placated.

Before Mum could tell her that no, Sirius was as much of a terror at noon as he was being now, Dad cut in. "Perhaps they _are_ just a bit overtired," he said. He pulled out his wand and finally dried Sirius, Anna, and I off. "There's a grate around here; we can probably get them all home by floo powder."

"Mum, can I go with Sirius and Reg instead of home to an empty house?" Rabastan asked as his mother opened her mouth— no doubt to tell him it was about time he went home, too.

"If their parents say it's all right."

"It's fine," Dad answered. I think he was just trying to avoid another conflict. "Now all three of you just please get out of here before something else happens."

All of us thought it wisest to obey— even Sirius, who lived to cause scenes— and we went through the grate to Grimmauld Place without further complaint. Well, at least not until we got there.

"I cannot believe her," Sirius declared. "It's not as if I actually picked Anna up and deposited her in the wine. She fell. I scared the hell out of her to maker her fall, but she fell all on her own."

"Sirius, quit while you're ahead," I advised him, wiping the soot off of my glasses. Anna leapt from my shoulders to the table and stretched luxuriously, flexing her claws.

"Thanks, Black," Rabastan announced, stepping out of the grate after us. "You do realize it's your fault we got kicked out?"

Sirius glared at him. Around our parents, they were on first name terms, but around me neither my brother nor my best friend did me the favor of even being civil to each other. Finally he shook his head and started up the stairs.

"Where are you going?" Rabastan demanded.

"To change," Sirius answered with a shrug. "You might not mind, Lestrange, but I am _not_ going to stay in dress robes any longer than I have to."

Rabastan shook his head as Sirius disappeared and unbuttoned his collar. "Idiot," he mumbled.

"I can't argue with you there."

"Who can?" Rabastan sat down at the kitchen table and scratched Anna's ears absently. "You know, if you're not careful you might have another cousin in love."

"Andromeda?" I asked incredulously. "I spent half the night talking to Meda, and I can promise you that she was way too lucid to be in love."

"You do have three cousins, Reg. Clearly you didn't see the way Narcissa and Lucius Malfoy were looking at each other."

"Best if I don't think about it, probably. If anyone tells my uncle Malfoy's as good as dead, you know— he's really overprotective. But Malfoy dead might not be too bad; frankly I think he's a conceited pain in the—"

"Who is?" Sirius asked. He'd come back downstairs, and he dropped into the seat beside mine.

"Rabastan thinks Cissy's in love," I said, changing the subject so Sirius didn't wind up cursing someone.

"Yeah, she is. With Malfoy." Sirius made a face. "I mean, I don't mean to offend you or anything, Lestrange, but Bella and your brother were made for each other. Not every man is gonna let her destroy the living room because she failed to kill me. I s'pose I've got to condone _them_. But Cissy and Malfoy. . . ." He shuddered. "That's as bad as Snivellus falling in love."

I shook my head. "Malfoy's conceited, but otherwise he's not horrible. And why am I always the last to know?"

"Because we have to tell you about it to get your nose out of a book to look. You should've been a Ravenclaw," Sirius answered. "And anyway, I'm not sure Meda's noticed yet either, and Cissy _is_ her sister."

I rolled my eyes. Then I glanced around the kitchen and my eyes landed on the radio. "I wonder if the Scotland-France Quidditch game is over yet," I remarked absently.

"Let's find out. It's better than arguing over Cissy's stupid love life," Sirius answered, going over to it to switch it on.

When Mum and Dad got home around four in the morning, the three of us were still sitting by the radio, and Sirius and Rabastan were in a deep argument about wether or not the last foul the referee had called really _was_ a foul. It was better than the things they usually argued about, so I hadn't said anything. Mum stared at us a minute, her eyes boring into the back of Sirius's head, and then she shook her head and started upstairs. Dad, on the other hand, gently lay his hands on our shoulders and said, "Bed, boys." He nodded to Rabastan. "I'll take you home."

"But—" the three of us started simultaneously.

"The final score'll be in the _Daily Prophet,_ or at least the _Evening Prophet. _You really do need sleep, and anyway, Meda's taking the two of you school-shopping tomorrow," Dad told us. "I would hate to have to go chase you out of bed when she gets here. And I told Gaius I'd take Rabastan straight home. Bed, now."

Sirius launched a few more obligatory protests. Because it was Quidditch, Dad just waved them away rather than yelled at him; he knew we were all just trying to stall in hopes that the snitch would be caught before Dad turned the radio off.

Finally, however, he won. "See you at school, Reg," Rabastan muttered.

"Yeah. See you."

"Oh, and Regulus?" Dad asked. "Make sure Sirius really does go to bed."

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Author's Note:** This is actually a chapter one from a story I wrote some time ago, back when Rabastan and Regulus's friendship was a sizeable part of my personal canon. However, I haven't posted in awhile and when I went through my files discovered that as an insight to Black family life when Sirius and Regulus were kids, this in fact stood very well on it's own. So, I hope you enjoyed it, feel free to tell me what you think! Cheers! — Loki 


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